Fuel filter for an internal combustion engine

ABSTRACT

The invention relates to a fuel filter for an internal combustion engine, comprising a filter housing ( 1 ) consisting especially of metal, and a filter element ( 6 ) and a pressure-regulating valve ( 7 ) located in said filter housing. The aim of the invention is to ensure that no noise originating from the pressure-regulating valve ( 7 ) is emitted. To this end, the pressure-regulating valve ( 7 ) is mounted in the filter housing ( 1 ) in such a way that vibrations are dampened.

[0001] This invention relates to a fuel filter according to the preamble of Patent claim 1.

[0002] Such fuel filters with pressure regulating valves are known from DE 195 23 626 A1, WO 97/12143, WO 97/01705 and EP 0 702 142 A1.

[0003] This invention is concerned with the problem of preventing all or at least most of the noise emanating from such a filter during operation.

[0004] An embodiment of a generic fuel filter according to the characterizing feature of Patent claim 1 presents a basic solution to this problem.

[0005] Expedient and advantageous embodiments are the object of the subclaims and are explained in greater detail in conjunction with the description of one embodiment.

[0006] This invention is based on the general idea of mounting the pressure regulating valve inside the filter housing in such a way that it is isolated from vibration. Pressure pulses which create vibrations occur during operation of a pressure regulating valve. The vibrations produced by the pressure pulses are transferred to the filter housing which is connected to the internal combustion engine or to a vehicle driven by the internal combustion engine either directly and/or via connecting lines. The noises to be prevented according to this invention occur due to vibrations transmitted to the filter housing by the pressure regulating valve.

[0007] The fuel filter known from European Patent 0 702 142 A1 does not have the complete vibration isolation of the pressure regulating valve according to this invention. In that case, there is always a fixed, vibration-transmitting connection between the pressure regulating valve and the filter housing at least in an area of the pressure regulating valve.

[0008] Of the embodiments illustrated in the drawing, the following are each shown in a longitudinal sectional view:

[0009]FIG. 1 a line filter with a pressure regulating valve mounted at two points in the filter housing in a vibration-damping manner,

[0010]FIG. 2 a line filter with a pressure regulating valve mounted in the filter housing only via a vibration-damping mount.

[0011] In the embodiment according to FIG. 1, a line filter housing 1 made of metal has two flow-through connections 2, 3, 4 and 5 on each of its opposing end faces where the connections project outward. In the case of a line filter for an internal combustion engine, these connections 2, 3, 4 and 5 have the following function. Connection 2 carries fuel from the fuel tank into the filter housing 1, where the fuel flows through the ring filter element 6 from the outside radially toward the inside radially in accordance with the flow arrows indicated in the figure, and then it comes out of the filter housing 1 as the forward flow, passing through connection 3 to the internal combustion engine.

[0012] A pressure regulating valve 7, whose design is essentially known, is mounted in a vibration-damping manner between connections 4 and 5, whose function is described below. The vibration-damping mounts are each made of so-called hose gaskets 8 and 9 which are inserted by pressing. Due to these hose gaskets 8 and 9, which may also be gaskets of any other desired form, the pressure regulating valve 7 is essentially secured sufficiently in both radial and axial directions. In operation of the filter, it is additionally secured against axial displacement of the pressure regulating valve 7 by the hose gaskets 8, 9 by a ring bead 13 which serves as an axial stop and is molded in the connection 4 or 5. These ring beads 13 may be either directly adjacent axially to the respective gasket 8 or 9 or may also engage in the gasket axially and also press it radially for an axially slip-proof seating.

[0013] Vibrations cannot be transmitted from the pressure regulating valve 7 to the filter housing 1 through the hose gaskets 8 and 9, which are made of an elastic material, or at least the vibration cannot be transmitted to such an extent that vibration-induced noise would be caused by filter housing 1.

[0014] Fuel released by the pressure regulating valve 7 to flow back into the tank flows back into the tank through connection 4. The pressure regulating valve is vented through connection 5 to be able to work against atmospheric pressure in a known manner.

[0015] In the filter embodiment according to FIG. 2, the connection 5, which is present in the design according to FIG. 1 for venting the pressure regulating valve 7, is omitted. Otherwise, the function of the line filter according to FIG. 2 is the same as that of the filter according to FIG. 1. Therefore, parts having the same functions are labeled with the same reference notation. Due to the use of a pressure regulating valve 7′ which does not have a vent connection, a different mounting of the pressure regulating valve 7′ is obtained in the embodiment according to FIG. 2 in comparison with that according to FIG. 1. The vent connection 12 in the embodiment according to FIG. 1 is sealed in the embodiment according to FIG. 2, i.e., it is not functional, and it serves there only as a retaining element. Although the pressure regulating valve 7′ has the same mounting in the case of its projecting connection 11 as in the embodiment according to FIG. 1, it is mounted on its opposite end face in a closed end disk 10 of filter element 6. In one embodiment of end disk 10 made of a plastic which has a damping effect, it is possible under some circumstances to completely omit the use of an additional vibration-damping mount between the pressure regulating valve 7′ and the end disk 10. In the embodiment illustrated here, however, a separate, vibration-damping mount in the form of a hose gasket 9 is again used. 

1. A fuel filter for an internal combustion engine having a filter housing made of metal in particular and a filter element and pressure regulating valve each mounted separately in it, characterized in that the pressure regulating valve (7) is mounted in the filter housing (1) in such a manner that vibration is damped.
 2. The fuel filter according to claim 1, characterized in that a vibration-damping mount (8, 9) is provided on opposite end faces of the pressure regulating valve (7) with an arrangement having the same axis.
 3. The fuel filter according to claim 1, characterized in that at least one of the vibration-damping mounts (9) is formed by the filter element (6).
 4. The fuel filter according to one of the preceding claims, characterized by the features: the pressure regulating valve (7, 7′) is equipped with at least one flow-through connection (11) which projects outward, the minimum of one connection (11) engages in a respective opening in the filter housing (1) on the end face at a radial distance, the annular space between the minimum of one connection (11) and the respective opening in the filter housing (1) is filled with sealing material (8) pressed between this connection (11) and the edge of the filter housing opening.
 5. The fuel filter according to one of the preceding claims, characterized in that the sealing material is in the form of a hose gasket (8, 9).
 6. The fuel filter according to one of the preceding claims, characterized in that the pressure regulating valve (7) is equipped with two connections (11, 12) approximately opposite one another and having the same axis.
 7. The fuel filter according to one of the preceding claims, characterized in that a pressure regulating valve (7′) which is equipped with only one connection (11) is also supported on an end face of an adjacent end disk (10) of the filter element, said end face being opposite the single connection (11). 